This invention relates to switching apparatus for low current switching, e.g. microprocessor level signals. More particularly, this invention relates to such apparatus having a detent structure which provides tactile feedback to the operator. Still more particularly, the invention pertains to improved detent apparatus wherein the tactile feedback can readily be varied during manufacture to assimilate that of power current switch apparatus.
The increasing use of computers has made multiplexing attractive in many consumer applications, and as a result, a need exists for switches interfaceable with microprocessor level signals. An automotive passenger car provides a good example of such application, although the switching apparatus of this invention is not limited to that application. Convenience functions in passenger cars such as the adjustment of windows, seats, mirrors, etc., are controlled by multiple switches ganged within a single package commonly located in the arm rest of a door. Such switches are designed to switch power directly to the actuators such as motors and solenoids for these items and require large, heavy cable harnesses to pass through the passenger door hinge area to be routed throughout the chassis and into other doors.
The state of the art passenger car has on-board computers for the monitoring and control of several operational functions of the engine and related components. Since the computer is already on-board, it is desirable to incorporate multiplexing of the convenience function controls with the computer. However, it is preferred to maintain the heavy duty feel, i.e. size, shape and detent characteristics, of the state of the art power switches presently being used, particularly in certain regions of the car such as the door arm rest. It is also desirable to provide such switch designs which can be readily and predictably varied during manufacture as to the tactile feedback provided in operation to meet varying specifications of the automobile manufacturers. Another feature to be considered is the capability for back lighting within the switch package that can provide a common look with the styling in other regions of the car. These features must be incorporated in a package that does not increase the footprint, i.e. the square inch surface area, and in many cases the depth and/or volume over present switches and that may be assembled at a competitive cost with present power switches which have been refined over a long time for mass production at low cost.